Get onto/on/to someone about something

1.You need to get onto your landlord about that leaky roof.
2.You need to get on your landlord about that leaky roof.
3.You need to get to your landlord about that leaky roof.

I wonder what are the differences in meaning.

I think they're all the same thing in meaning, more or less, but I'm not sure about whether 2 is correct English.